James Franco has revealed why he wanted to star in Oz The Great And Powerful - so he could walk on the yellow brick road.

The 34-year-old stars as small-time magician Oscar Diggs, also known as the Wizard of Oz, in Sam Raimi's prequel, and admitted that working on the set was "surreal".

"I just always wanted to walk down the yellow brick road and this was my chance. It was pretty incredible. When they brought out that set and we started doing scenes on it, it was quite surreal," he said.

James - who shares screen time with Michelle Williams, Mila Kunis and Rachel Weisz - admitted that the role was his childhood dream come true.

"Not only was it a beautiful set, it also felt like I was acting in a world that had been part of my childhood. I loved the book as a child - they were one of the first books I read for pleasure out of my school. I remember going through all 14-15 books that L Frank Baum wrote as fast as I could," he recalled.

James explained that Sam's origins story isn't a remake of the 1939 film, which starred Judy Garland as Dorothy.

"The 1939 film is of course beloved by many people, myself included. One of the things I knew that they'd be able to improve on with this film was the rendering of Oz - they'd be able to create a spectacular world that's fully engaging," he said.